Using traffic micro-simulation to test route diversion as a real-time crash prevention strategy on freeways

The purpose of this study is to examine the potential of route diversion for reducing the real-time crash risk along a typical urban freeway. The PARAMICS micro-simulation software package was used to simulate the Interstate-4 corridor in Florida. The crash risk along the freeway was determined using models created by the authors that yielded values of both the rear-end and lane-change crash risks using real-time loop detector data. Route diversion was applied at different network loading levels to determine the effects of diverting vehicles at different levels of congestion. The study shows that route diversion is an effective crash prevention strategy when the freeway is operating in uncongested conditions. In this situation, the crash risk decreases between the locations where vehicles are diverted from and where the diverted vehicles re-enter the freeway. In general, diverting more vehicles and diverting vehicles further downstream serves to improve the overall safety benefits experienced. The only downside to diverting more vehicles or diverting them further downstream is the increased overall travel time; however, the travel time increase encountered in this study was within acceptable limits of about 5% during the uncongested conditions.